This invention relates to an induction control system for an internal combustion engine and more particularly to an improved induction system and control therefor that improves performance during transitional stages of engine operation.
Recently it has been proposed to provide an internal combustion engine with a relatively small auxiliary induction system through which the charge is supplied to the combustion chambers at idle and low loads. Such an arrangement increases the velocity of charge delivered to the chambers and the resulting turbulence improves running at low load conditions. Furthermore, both fuel economy and exhaust emission control are improved with such an arrangement. The charge requirements for the engine at higher loads are supplied primarily through a relatively large main induction system. The proportion of flow to the chambers through the main and auxiliary induction systems is controlled by means of a throttle valve arrangement.
Various arrangements have been proposed for controlling the throttle valves so as to achieve the desired flow relationship. In one form of such control, the amount of charge flowing through the main induction system is regulated by means of an automatically controlled valve. Such a valve may be responsive to the air flow though the induction system so that the valve will be opened as the air flow increases to deliver an increasing amount of the charge to the chambers through the main induction system. Although such automatic arrangements are satisfactory, certain problems may be encountered in conjunction with transient conditions. For example, under extreme acceleration the air flow may not increase at a rapid enough rate so as to effect opening of the control valve of the main induction system at a rapid enough rate.
It is, therefore, a principal object of this invention to provide an improved control device for a compound induction system of an internal combustion engine.
It is another object of this invention to provide an improved control valve arrangement for an engine having both a main and an auxiliary induction system.